1. Field of the Invention
The present invention relates to an image display apparatus that converts an input image to a display image and displays the display image, an image display method, and a recording medium.
2. Description of the Related Art
There are imaging apparatuses such as a digital camera that develops (converts) raw data input from an image sensor such as a charge-coupling device (CCD) sensor or a complementary metal-oxide semiconductor (CMOS) sensor into Joint Photographic Experts Group (JPEG) data. The imaging apparatus then records the JPEG data on a recording medium. Further, there are imaging apparatuses that record raw data as is or as close to the original raw data as possible.
In the raw data, one pixel is often expressed by 12 bits or greater. On the other hand, in an image display apparatus such as a liquid crystal display (LCD) panel in the digital camera or a monitor of a personal computer (PC), one pixel is expressed by 8 bits. Therefore, if the raw image is developed and converted to the JPEG image, one pixel is reduced to 8 bits. An image in which one pixel is expressed by 12 bits is referred to as an “image in which a bit depth is 12 bits”, and hereinafter will be referred to as a “12-bit image”.
Further, Japanese Patent Application Laid-Open No. 2003-250067 discusses an imaging apparatus that converts light entering an optical system into image data, i.e., an electric signal. When displaying the image data on a display unit, the imaging apparatus notifies a user on a portion of the image data in which luminance is greater than or equal to an upper limit value (i.e., overexposed) or is less than or equal to a lower limit value (i.e., underexposed). In other words, the imaging apparatus notifies on a portion in which there is color saturation.
Conventionally, when there is saturation in the displayed JPEG image, which is converted from the raw image, there are cases where the original raw image is not saturated so that the colors are correctly expressed in the original raw image.
However, Japanese Patent Application Laid-Open No. 2003-250067 only discusses notifying on whether the 8-bit image to be displayed is saturated.
As a result, when the imaging apparatus or the image display apparatus displays an image of lower bit depth after conversion (e.g., an 8-bit image), the user cannot confirm whether the image of higher bit depth before conversion (e.g., a 12-bit image) is saturated.